People of ACM - Naehyuck Chang

March 19, 2015

Naehyuck Chang is a professor in the Department of Electrical Engineering at Korea Advanced Institute of Science and Technology (KAIST). Prior to that, he was with the Department of Computer Science and Engineering, Seoul National University. Chang also served as a Vice Dean of College of Engineering, Seoul National University. He has also served on editorial boards of ACM Transactions on Embedded Computing Systems and several IEEE publications, and served on program committees of several design automation conferences.

Chang's research interests include low-power embedded systems and Design Automation of Things, such as systematic design and optimization of energy storage systems and electric vehicles. He is Editor-in-Chief of ACM Transactions on Design Automation of Electronic Systems, Chair of SIGDA, ACM's Special Interest Group on Design Automation, and Executive Committee Member of DAC 2015. He is an ACM Distinguished Scientist and an IEEE Fellow.

Chang received PhD, MS and BS degrees from the Department of Control and Instrumentation at Seoul National University.

What triggered your desire to change the culture of the University Booth (Ubooth) at the Design Automation Conference (DAC) in 2000 to incorporate prototype demonstrations of your hardware systems rather than rely on poster presentations or software demonstrations?

Electronic design automation (EDA) research has fostered intimate cooperation between industry and academia for the past 50 years. The University Booth (Ubooth) at the Design Automation Conference (DAC) was founded by ACM SIGDA to bring academic research and development in line with industry practices, providing exhibition opportunities to academia on the same professional exhibition floor at DAC. I believe academic research presented at DAC is the foundation of successful evolution in industry. However, the actual demonstrations thus far had primarily been of posters or software only—unlike professional booths on the same exhibition floor--because it was not easy for foreign university people to make trips to DAC with large equipment due to budget constraints.

I believed the Ubooth would be more visible if demonstrations maintained a good balance between software and hardware. I decided to change the Ubooth culture, as our team has developed numerous examples of low­power embedded system hardware. I also believed such effort would set a good example for other Ubooth participants and leverage practical aspects of low­power system research in academia.

While it was not an easy task, I brought not only the hardware demonstration systems to Ubooth from Korea but also numerous instruments, spare parts and debugging tools that filled several cargo boxes in order to prepare for potential damage during the intercontinental trip. Several times, our team had to debug broken demonstration systems in a hotel room overnight but they never failed in live demonstrations.

Because hybrid energy storage systems (HESS) are not allowed to be shipped with batteries installed, I shipped the HESS prototype from Korea to Los Angeles with no batteries, purchased batteries in the US, and reassembled the HESS in Los Angeles for the Ubooth demonstration. Our team then drove from Los Angeles to San Francisco in 2012, from Los Angeles to Austin in 2013 to bring a 19­inch rack HESS to the exhibition. Looking back, packing, shipping overseas, transporting on ground, debugging, and demonstrating on site resembled a diehard military operation with participation of several graduate students. Our demonstrations were arduous but gratifying and were always successful. Our team was able to build a stronger reputation alongside that of Ubooth for the past 14 years continuously.

As an Executive Committee member of the 52nd DAC this June, what led you to participate in "52 Weeks of DAC" blog posts a year before the event, and what do you hope to achieve by this communications experiment?

DAC is one of the most leading conferences that continues to develop new initiatives and outreach to new people. The EDA community believes in the strengths of the EDA theories, tools and methodologies that can handle large­scale problems while providing quality solutions that are close to optimal. The DAC blog is one of the most successful activities to reach out to people and draw more attention to the new initiative of DAC. We look forward to having more younger researchers at DAC, thanks to the new initiatives and their encouragement/introduction through the DAC blog.

How has your research been received on the Hybrid Electrical Energy Storage Systems (HESS) you developed to replace conventional homogenous energy storage systems?

The HESS research can be positioned as a representative example to demonstrate how EDA methods can contribute to open problems in other areas. The HESS idea is to overcome the natural limitation of batteries through the use of system­level optimization, which is a representative approach of system­level design methodologies in the EDA community. This research has been recognized not only in the EDA community but energy systems and power electronics community as well. This is a good example of how international collaborations can be beneficial in terms of research competitiveness and cultivating younger researchers. This work is a joint research between Korea Advanced Institute of Science and Technology (KAIST) and the University of Southern California (USC).

As a prolific inventor and veteran editor of design automation technology research, what advice would you give to young people considering careers in computing?

For the past decades, layered optimization such as device­level, circuit­level, architecture­level, system­level, software­level, etc., could systematically optimize computing systems. One can see this from 37 Special Interest Groups (SIGs) of the ACM. However, the boundaries of layers are rapidly collapsing, and cross­layer optimization is becoming a way to overcome the barriers that block Moore's Law. I would like to recommend younger researchers to be brave enough to look beyond the area boundaries. Future computing is beyond computing. One's primary area fundamentals will always be the basis. In addition, I would encourage younger researchers to be open to various applications that may be beyond computing.